SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '539b5481015ab37380d61976d4e9f6357522e7d86283da792f60de64f215ce6a' 
  AND token = 'Wu7hmDeHXQpBvrhO4uNdBgGXYBYGMVGoOpRncwxwSa4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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