SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '341c510d420287b0922771b5f7126d1399a42a480a85dadcc20fd81ae9ce6a8c' 
  AND token = 'hkQ7LlEIep5meFFWIUqhDPrQZxzciKOM1Uv4SUROwzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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