SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87829a6e6011680dd59d163f67a984ca4731e94c3868b52f31814e807dd961e6' 
  AND token = 'o2aTKr0ZIUAEuVY9Y+P1dlu1rRXfvT959dlEe57zNwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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