SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcb7446bd8e283bb25df3644174805727b0485c5ecf84a7bc2f72eab9474f49b' 
  AND token = 'zh/ZdHHTVb1VABMEDC6GTvFZPK6qz5sYKRcGZ0W6nMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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