SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e729974dc66b0732d1f01dd5a361f07be1bfa0e237ac7809ab8d684a34d14fa' 
  AND token = 'cPVLlaNNOfQwVJh4dhIBZUgf5SPvrs1+RHvNEYJFtXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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