SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0b611bc83a4a3130fc8c72d97cffb13d5159df06c694021adf4e9057af30f210' 
  AND token = 'JzuNcdqMMoevUMvsYhlkV0uIuY/fe3b5MhBvnPBoHNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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