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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8cd8fcd53b7100568b15de23bf777fc69fecce0071c1cf1493093064578b2f2' 
  AND token = '3oZySDk+NkCTe3UgVJ1RliNHrFw4/mCgb1+59Re0+Tc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}