SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f984905729771cb02ff71888f5a841a71a25e266d73adb64efea17b630b9380d' 
  AND token = 'AwffU9yXMas1aI+HF3MYLIuWsEL4zJZid6yE7deowyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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