SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd99708e47dafdc387ef6c03846aae3590a44ca7e126b1216514b20922727d3bc' 
  AND token = 'RSaK9cKrt2zdKd5G4xoKf6IroERQVFtnvpAF4q2TR9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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