SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '881f5ae46875b5bbac9816db727f0eff99d1a64e8ffc28d893c29116384589da' 
  AND token = 'GHWRnOXLphSdJRQO5LYMj/2V02HNZ/PTSuZQ/EUPM8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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