SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f898b41af050ea0ce2ec29275345a29db0e5eac85626d81759f6ff79905740e8' 
  AND token = 'JqFidA7ewO0Op5LZweoMyy0ELQ52Ncz6vXRJ9E5g8RM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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