SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '623b94eb7afc88af01343b551beee1cef957eb7f739b41ef7dd8819ed8d3c2e1' 
  AND token = 'A1ElKqYazz7lfdG3SpF3WzYoBaFjWiqXP8Q3YiBXo44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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