SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cb881af188de3dff8587061bd8e330f5dc2eedd004c092f410acf9ec5b0273ba' 
  AND token = 'ea5/h2ZjH5jzJyh5QIAMnqbp31AnPLzSpwElN3yO91g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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