SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb392aaaa73f2dd1c36d0f4768416d36426b938f02e99c9ff4549d86a24074ab' 
  AND token = '+d0FdGr+VsqFSL1RhsLewyhDfcbQsK/U9w0GzYKLz4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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