SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4187ecf373c47a87b784280e455da7764b09b41c9598a10a8a98c6484b452317' 
  AND token = 'e2DWHKjHzmDrNEE7DkFLdN+TbrGqe4nIGnvaNqrgNJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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