SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b90615723de8be0bffed264776f56555d23bde134c819a1957c23e5f4bcc6985' 
  AND token = 'KP/2xmRmQVlYHchuqmAUz0Mn4qucHCyaWD6pvLX8S64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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