SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64d0833b2d398bc8e1d9f8257915ef89e537673dc222e3d4061c14459f84167e' 
  AND token = 'dj4CYKq0nukFI6UwNLIRchTv3HSDwkvcKHDESWINCrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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