SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1901d087caaa409408d7fe02fdeef2faab318a70efe1cb71541584045809d0f5' 
  AND token = 'yckKO0lSzCuYPcIYXavckv7wYTvXjl/a7qNno0FCDBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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