SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b056bd76a6457983e9c5c850aea4f4c6b18dc7f138bcb05d4913a595d7e298e6' 
  AND token = 'DuH7WTH0aDJuEXrGgpZHUYhxOs7g+VHvWFiRJ5rvqwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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