SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3c6c8d7a59626f5f569e16ab7f929de5beb73f8ecd6237221e7e19f17bb036c1' 
  AND token = '+mfDzVu99UU0w5flyUCow2xAV2cWvXsGticxrbfyT/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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