SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c21880e593f5283bfc4cdc65f8868c4976054be0503896b1dcda57434d90db98' 
  AND token = 'AzIJIGSztXcblXxI7JXqHFQxhQzaHXSftx9ymvDAcTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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