SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4669c04353a5fd55527eda6858b3359dd76fdacd2d1f1ea88ee805e5d58c5be0' 
  AND token = '5YcBUFzLQUVwrGC+xniy7Iz5d82z/l80g/eVAiFZuyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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