SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8db3dff35c408596b9d99efbade2c6c6d34a53d8214b6a93d29658b6d51c7e5c' 
  AND token = 'YvSeCZeg/Q/bJxGeVaCaFF37I8VsXquuXRKurn+7wCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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