SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b9d282673cb09e4553f3c42e7306a94f18729a6fb4d10c8bd2605bddf9f0252' 
  AND token = 'nQnEahDSnBBz1JN8WlC6gWjnSygJjVeHd7EaMOH/sZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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