SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c82f19c59659ae473cc68809b2144b6c20fd49bb5e7c3a51146414937708e6eb' 
  AND token = 'SUvXhQJlLfsB0Nms3U3DYGom8HYil7ABQHvEClBs+uE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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