SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39861a40ff95bfbc5bfcf94d30fd09be764d7d6d70e84bd68c6d090d935b626a' 
  AND token = 'ku/REm0pPRWSZge5N7k+Tyz+hJJtQsDfCrLowuFekg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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