SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a666d073232a69430c03896d37340d93974f5cdf672793c59db9b5c56b0e163' 
  AND token = 'myEQtkGUNkGefRt/VTmmZsRhmb6EyxyDae0zujaVOSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}