SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7ff5e4d017089075e8b1a18b04231603f82323cc621098f77c55f5f2e75a163' 
  AND token = 'ZNt8ul1T1pvgAlzbDC7ntSiBRutwpeaaZihVRfu25CY=' 
  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"
    }
  }
}