SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8dbef47c70cbd54743dfa18b639760dda48cba3ae60e52b4903b59cb15c41492' 
  AND token = 'my5ejHjgboHiROqb6qQQTVFNNjFqkTnZO10IgyySDdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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