SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccc40dbd8142314350b519d53851b0b78f0efabc36a7b62b76e140b0277b13f3' 
  AND token = 'MGZ9hoFRlY83mQXPZq5v1eZ02uz2EXP/WrKz9rmgv2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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