SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '314a6f8a4c5bd79f5277fd916bd7c01ad17c76f481fabb9b96a84652be5832f5' 
  AND token = 'B/FVfwj8QbykaIUwlxq8FKAwRgPSu4LpPdSaJcZ8pNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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