SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34a83ef9c441ad87276592934f2cd504652d9684e2be6f3ec141b27bb44d6188' 
  AND token = 'BukHaiMjFmhebdv3JSIQmyVMQPD0LVpx2jZbcU0LIGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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