SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3863ca383fc59d3a14589bdc9f873e28560c8db21bc61c4be62a2871a374ea44' 
  AND token = 'kc5n1HPatuEMVbcLt5i2fyloqYVPhZ6LSKNvvQ4Dlzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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