SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5ac784d571c83d9bf746bc1cd4cf9b553fc14e21e194a7142606be056ed0df00' 
  AND token = 'zHocp2ZunJm3Y4bKXzrdrIpY//PKoBjP+CWUXTCSwSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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