SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7589359c660b0e88234bc8e2fbe97982e6525b3d81a013a097ac8a5dbf035730' 
  AND token = 'Yj+qezBdgkuUlHNO5iHYMqhpkCH5Bug1VwsGKcc3XbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}