SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29d9fda2952c81dccc2815b1b1f2a7560fb4ecf48e1dd393683238071fd7edae' 
  AND token = 'VcdJZDgHRQB4wzarUsaeN6wJjGAF5D+3QTkr2uGVPuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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