SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '042d7112cd976d94f271e327a52cd84617b5bcab66a727453a670e8b819f88a8' 
  AND token = 'gV8wzh+iGPq5WbdYW7nh1l4r1Zi2hSncCggOpXjOPiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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