SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96b9eb269a3fef3cecb5bf77374f438bf2facd237e7d9e316281f8223b0070b1' 
  AND token = '98WUs4ACeKwum9j200yIQUYT7w3yw704od1n1NNmUu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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