SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '326a05f4eeed15e14d4354c0f18edddd310f79001331d1a645e43c7c8c99b649' 
  AND token = 'izQpa+/HcxsSsV7HqAj2vjnv8GsZyk+jVh6QnWwra2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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