SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f73387dd88489d539bc526612384904a31a66ddb48dc1c4a2a2c81090ba7d1f' 
  AND token = 'QuptBQ/DbjdkQNFQLSb1J0kWGkiBWpje0rTect0tj0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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