SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ad11b96b326b8612cc0a0730fbc76df6414f951cb41ca1b9a9e0c24cff5c5974' 
  AND token = 'TM+5Pm79ignUUZqtqkFXgZ69evlU9Yh8IfM6WhcwKG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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