SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '717f6ac96fcb4f7978745430dfc408fba904704779f435645f443856ae249f2e' 
  AND token = 'EFPRZMdzjM+fC4xAdTq95jz2mzMGS1zZQvr++95VkqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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