SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f2c22b7c468d39d22ae1769534d9d253d90c85e6086c99fc3a4fae4c623030d' 
  AND token = '63MdmL5yhKubgq+3mP5txIVwS4XlOip8+bGHHQPFhWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}