SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffe7c47e8b99e97e6fd4560f87f5359c1f24c3734abd3f7ef8b683bf6916dd02' 
  AND token = 'SGkJ+VhVBnh5NwFd+A185RRNqcJKFv6IMWFNJcvwOKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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