SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8b2f18c9669ef586536678a2095b0eccd706147b5b98cff7ea628c1a59a27989' 
  AND token = 'o/QM7/TApI2WEezhg7bBW/gZ4RIwuKA8KJLTKi9K+Gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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