SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56fa5b4ea5f9ac7f7ead49a5e40d43d626aab33371273fd2dd0916868b3a4a28' 
  AND token = 'DdEiZhBp5+n61JdZLV9M2cg9Tn7ktVdEDetqstbkPC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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