SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c61adda4900982cd698f1b9605b8b0c345eee9409f7b11555c85356151d2a56a' 
  AND token = 't+wNEkph4O2DsQcfCk2fW+okJTfU6xbC+eQ3cedhjIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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