SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2adbe8b94a5ede81986eef84b8ad66eb9c610f77294b3c9418c67b68067208e' 
  AND token = 'TvTZb+IXrSr64d+w8CHE9dOgU2iXT/ElHLyLklQ2mj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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