SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '479fcc541ea861aeca7ad93616be7d4cabcca0c0b6f4fdce4bca5c8d3aad844e' 
  AND token = 'kPfcKF+K4LsY2FvOQJaFXUaCcUPZYkE8HIfj7vcO/9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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