SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f070356eeaeaefd29ad1976557b444e1f5d47f255d362794c81b70dac052ff3' 
  AND token = 'FW0hK1KZwhrnJrCLfPEt0k78aymCzapI3Yf/joZHhxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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