SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f4b762dc4db9c7a57aac619086cda7a2dfcd4de817c052370ec60b4d68797c0a' 
  AND token = 'qB7sVXDozfUOEqF7dSGZ0ZuyEWl7nMy7CNPhRFkGTwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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