SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bbcaff5655a3b3d057b4bddf3ce749d4067e46ca347e9ef0726f4abdbb73bf20' 
  AND token = 'FXTIuQ18s+mEZ3CLwTy71XrdaWwvaHDdbjgLAQbSZKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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