SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac65159f3ecaf94d1136e62aee06d0d9671d07336a631daaf54b41ab50ec026a' 
  AND token = 'lmGmMmzZA5z3RYihqWdjVfelaNeLFOoe8Wqo440gjYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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