SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17c553c5ba56520fede63ffbfc925e714820326922f4f34718143a42e5540bb7' 
  AND token = '50lpm6KiDLUz96Hv+f0tbn1s6yOErHkNWEP0cLIbUKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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