SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5516214a55bdf303ea7ec7006b0aad3fc74c8674afd400a067e6fd477667a8f4' 
  AND token = 'r3FvZQ569NpEcArPOokTQjUY48baik/XVQvCUCeNBf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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