SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7bef383779550ce1294955c92417cfae4039a8c6cbb93187f38702552b2e75f' 
  AND token = 'SZzKVKmJoA5J4H2dXsZRudHkWwiVn/kK1eP35r1s7sA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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