SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1f642472e6692ac73febcdd5ecd9d4b735cf5c65e7ef8524feeaa6c43db0b089' 
  AND token = 'UVgKqzMIlEwJi7/hy4zXZzjXNSyXXjwTz7KS2lIZw3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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