SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cc801bb84931d7b206293d52640349c2dcfdea80706a6671fd1a88867ad2b49' 
  AND token = 'P3xaTBaijC8PAv+9LPjXmggTsA4TVsLODoeewEgXOIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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