SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ebfa2cfc90d7767ba84e2feffa4bc5b66bb17f328ad0d09872ffebb03c00635' 
  AND token = 'QUvUtClZn8c3ElLrqkhfjfPtVZZW8xQEIo5b+KSWxKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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