SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acac620e875f2757e984c76863aaa3a9ff249d85e09dfe617ebc6289657ea53e' 
  AND token = 'RezlIZAkVQkNWb3tu9a3JhWYthTiKmPIgcZzgBNg4qQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00008

JSON explain

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