SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6ac168314745f4d9ea787e984a800bf2979f9d5c31b07e309d62dd9c72538f7' 
  AND token = 'RtXqBn/Jy8WBJdEHvsLpvYJWTzCG4xFmgRbrKnoJNUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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