SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8a7dbcc9ec2984d114ee47aed9b65feeb54079134e343bfdcc23246ded40da8' 
  AND token = 'OxZoMYcYhU0XxrEcoiVTUJz9H1G0+EEZO76fie64zwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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