SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f4240191cfedf62fbc98b4d1d478881415d0e0cad1a773fad06149023ff9e479' 
  AND token = 'BXcFLMrPITL0dQk9/cxpDoD4VCZX5jhGrIMRN5PKDog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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