SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'adda5e32bcc550e6abd47927f09e0870c2c1a2f7c9a013c925b9066919b747bf' 
  AND token = 'rMdTYkPMaJxpUEUzn+Y7VhxGnah6LBvgwuqXRS0RRqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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