SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6802c177d64bfe6ed5c322d985e8cd545845197e323478f3d52b73985ece2c17' 
  AND token = 'EezVkA81kqbOcyz3a9xs//1Nu/cTlRj5wJUzqBoD9Bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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