SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ae3a12b17fa4b5a1547b68e9950462d073b81aa5ea825ae6c1a6dcccd86c512' 
  AND token = 'FnaH7SMIMtej+i31xw/AJMy5hWWv6Qprtj0b80Ed/j8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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