SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27339e2dac23ab28fd2ef4961e56caa8508e28184a7b4fc1ff4ead997babb413' 
  AND token = '7uLnDOSgpEoGI1TxQkxUXJt8dra0C3/eleoWY+kqE40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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