SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8a4fd8f3d58956cdf9c378cdce9728e2c99d7e744ccfe12ab08781a7cb53e25' 
  AND token = '9l+NVxCYoxN9cuQjKBrVW0qlPcVkJ7zuUwYQmh1LHto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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