SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f68ce913ddebaad1dd930f347c79701bff9cc55958522d92d24b533fe4b46521' 
  AND token = '+S6OIC/R4GSqv7VZHpLN/FnPyd0uAH8fXJJ8iz2zJ30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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