SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6a1aedf6ad066ce4e30192b8b4fbe7edee06db1f36b5ffa022d5ab896c3c017' 
  AND token = 'wC9fPcq6kVaRSZZVkYEdfQOHaiHHNY6wEZT+QSJc6E8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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