SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2609f5250f2b45557af3be5435810ad5e2f2f7c4ee60d89eb16738912da160ca' 
  AND token = 'SVJlt0qwr9fNmigQFQJsG/MMKi8PZ4dK6H/0LgaWjS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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