SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0e343b2b877f82a56e6f5649e56a1b26da56dcaa52becbf52491e8ad68d2243' 
  AND token = 'OwMpESTCpKzV+H5fNKRIVvvbXgxfmZpAhMvrtui9qrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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