SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3a1a77b7251bbe3508e452ec7475f7f7165afaafe8c7e913886db6de7ed64f29' 
  AND token = 'mCID+E1sTnnh3W4QJXL3slutz+guGyMttYDlifFklUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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